We shall now pass to the second reason. In the prehistrionic period a series of lyric questions and answers between chorus and coryphaeus was the nearest approach to a dialogue that was possible (see p. 10, above). With the invention of the first actor this interplay of question and answer, still lyrical in form, could be carried on by the actor and the chorus (including the coryphaeus). Such a duet, which came to be known as a _commus_, continued in use, especially for dirges, as long as the chorus lasted. Side by side with this, however, there quickly developed a non-lyric interchange of spoken lines between actor and coryphaeus. But not until the second actor was added did true dialogue in the modern sense become possible. Yet the poets could not at once make full use of even these simple resources. Our analysis of Aeschylus’ _Suppliants_ (pp. 163 f., above) shows that in two instances Danaus stood silent and unaddressed during a conversation between the other actor and the coryphaeus. Moreover, priority of usage constrained the playwrights to give the actor-coryphaeus dialogue precedence over actor-actor dialogue (cf. pp. 165 f., above). They seemed unable to weld the two types together with a technique which would employ all three persons at once. In the three-actor period the embarrassment of riches made their helplessness the more striking. “A” might engage in a dialogue with “B” while “C” remained inactive; then with “C” while “B” was silent; and finally “B” and “C” might converse, with “A” remaining passive. Often the transitions are marked or the longer speeches set off by a few more or less perfunctory verses (usually two) spoken by the coryphaeus. The type is not frequently worked out as completely as I have just indicated, but the principle is illustrated on a lesser scale in almost every play. Compare, for example, Euripides’ _Helen_, vss. 1186-1300, and _Andromache_, vss. 547-766. Such an arrangement, needless to say, falls far short of a genuine trialogue or tetralogue. Yet we must not be unfair in condemning this practice. The Greek poets were feeling their way and could not immediately attain to every refinement. Even in Shakespeare and the modern drama, despite centuries of continuous experimentation and the numerous examples of superior technique, the tandem arrangement of dialogue is still not uncommon. A half-step in advance consisted in the silent actor interrupting the dialogue with some electrifying utterance. For example, in Aeschylus’ _Libation-Bearers_ (458 B.C.), Clytemnestra’s appeal to Orestes on the score of her motherhood stays his hand in the very act of murdering her, and he weakly turns to his trusted friend, Pylades, for guidance. The latter’s ringing response, Wilt thou abjure half Loxias’ behest, The word of Pytho, and thy sacred troth? Hold all the world thy foe rather than Heaven [vss. 900-903, Warr’s translation],